Nestle Greek New Testament 1904
πάντα καθαρὰ τοῖς καθαροῖς· τοῖς δὲ μεμιαμμένοις καὶ ἀπίστοις οὐδὲν καθαρόν, ἀλλὰ μεμίανται αὐτῶν καὶ ὁ νοῦς καὶ ἡ συνείδησις.
why translation has been done this way
New International Version
To the pure, all things are pure, but to those who are corrupted and do not believe, nothing is pure. In fact, both their minds and consciences are corrupted.
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should be like that -
what is pure to pure and for not pure nothing is pure - they are inside not pure - not in mind not in consciences
panta katara tois katarois - clean things to clean people